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Palm Oil

March 9, 2004

Some interesting work was done in the palm oil industry. A Vincent Fiber Filter machine was used to filter suspended solids from the hot oil flow that subsequently goes to centrifuges. The objective is to improve separation performance, to reduce plugging, and to reduce abrasive wear of these centrifuges.

The testing was conducted in Costa Rica where there are a number of palm oil extraction facilities. The oil comes from the berries of the African palm, a tall and very bushy palm tree, usually with ferns growing on the trunk. Thousands of acres of banana plantation have been put to palms. The bunches at the crown of the tree are about 12" to 16" in diameter; the berries are about the size of large grapes.

Truck loads of bunches are delivered the processing plant and loaded into gondola railcars. Strings of half a dozen gondolas are pushed into long steam cooking tunnels. This loosens the berries from the stems. Next the gondolas are dumped into huge rotating drums where the bunches are tumbled so that the berries break loose, separating from the stems.

The berries are next cooked and crushed in vessels called digesters. These vessels, positioned over powerful screw presses, operate with 150 psi steam.

From the digester the berries go to twin 12" screw presses. These presses were made by Vetter (Germany) and Stork (Holland); one, and maybe both, of these firms have since left the market. The presses are of high capacity (12 MTPH) and torque. The press cake produced is extremely dry, only 40% moisture.

The press liquor from these presses contains oil, water, and sludge. The oil is separated and clarified in decanter tanks. Solids and water are removed with centrifuges and, in the tests, a Fiber Filter. The oil is mostly made into oleomargarine, although some is blended with soybean oil for commercial cooking.

The press cake goes through two cyclone separators or classifiers. In the first separation the hard kernels are separated from the pulp of the berry. In the second cyclone the pulp is separated and subsequently fed as fuel into B&W boilers.

The hard kernels are cracked in Ripplemills. The outer shell joins the flow to the boilers, while the inner seed is flaked in French and Rosscamp vertical roller mills. The seed, now a powder, is conveyed to digesters where it is cooked with 150 psi steam. From there it is fed into Anderson Expellers which, to Vincent at least, exert unimaginably high pressures. The solid fat in the seeds is converted to an oil that flows from the screens of the presses. This oil is of a higher quality than the oil extracted from the pulp of the berries. Rather than being made into oleomargarine, it is sold to the pharmaceutical and cosmetic industries.

It was found that a simple Series KP screw press was needed to squeeze liquid from the sludge produced by the Fiber Filter.